Cnidaria and echinoderms have radial symmetry. Mollusks are bilaterally symmetrical. Cnidarians have no coelom or cephalization. Mollusks and echinoderms have true coelom and cephalization.
Cnidaria has two main body types, swimming jellyfish and sessile polyps, both of which are radially symmetrical and whose mouths are surrounded by tentacles containing stinging cells. Both forms have a single opening and body cavity used for digestion and respiration.
Many cnidarian species form colonies. A colony is a single organism composed of a jellyfish-like zoo or a polyp-like zoo or both (hence they are trimorphs). Cnidaria activity is coordinated by distributed neuronal networks and simple receptors. Some free-swimming species of cubozoas and scyphozoans have balance-sensitive statocysts, and some have simple eyes.
Not all cnidarians reproduce sexually. This is because many species have an asexual polyp stage and a complex sexual jellyfish life cycle. However, some have omitted the polyp or medusa stage, and the parasite class has evolved to have no morphology.
learn more about cnidarians here. https://brainly.com/question/1538731
#SPJ4
